It has been more than two years since the California Air Resources Board (CARB) committed to revise indirect land use change (ILUC) penalties assessed against certain biofuels as part of its Low Carbon Fuels Standard (LCFS). Since it went into effect, a federal district judge has ruled the LCFS unconstitutional; however, CARB was able to move forward with the law while litigation continues.

Since ILUC came to forefront, many peer-reviewed studies have been published that show CARB, along with other entities, have overstated the overall carbon intensity of corn ethanol. Despite the growing number of more accurate studies, CARB has yet to make any changes to the LCFS program’s indirect land use change estimates or direct carbon intensity values for corn ethanol. In response to the lack of action, the Renewable Fuels Association (RFA) sent a letter to Mary Nichols, CARB Chairwoman.

“I am writing to again encourage CARB to honor its commitments to expeditiously revise the ILUC penalty factor assessed against corn ethanol and to utilize the ‘best available science’ when determining direct [carbon intensity, or CI] values,” wrote RFA President and CEO Bob Dinneen. “Revising the direct and indirect CI values for corn ethanol would be much more than a mere academic exercise; rather, a continued failure to update these CI values will jeopardize the ability of regulated parties to reasonably comply with the LCFS program’s increasingly rigid CI standards in 2013, 2014 and beyond.”

Dinneen’s letter cites a number of reports and studies published in the past several years that demonstrate CARB’s corn ethanol carbon intensity estimates are “unjustifiably inflated.” The most recent study, conducted by GREET model creator Michael Wang at Argonne National Laboratory and published in Environmental Research Letters, found the carbon intensity of average corn ethanol to be 62 grams of CO2-equivalent per megajoule (g/MJ), including possible emissions from ILUC. That’s 38 percent lower than CARB’s current estimate of 99.4 g/MJ for average Midwest corn ethanol.

Dinneen cites several recent papers specifically related to ILUC  and writes “…based on newer data and improved methodologies, the independent estimates of corn ethanol ILUC produced since the LCFS  was finalized have generally trended in the range of 8 to 15 g/MJ. This compares to CARB’s ILUC estimate for corn ethanol of 30 g/MJ.” The letter continues, “Clearly, given the data and modeling results that have become available since the LCFS was adopted, CARB has no scientific basis or rationale to maintain its current CI scores for corn ethanol.”

Dinneen’s letter also reminds CARB that “…failure to revise corn ethanol direct and indirect CI values in a timely matter will greatly complicate compliance with the LCFS in 2013, 2014 and beyond.” In order to fully offset the deficits generated on CARBOB, the ethanol blended into E10 must possess a CI value of 83.6 g/MJ or lower in 2013. In 2014, ethanol must have a CI value of 76.7 g/MJ in order to fully offset CARBOB deficits.  “Because of CARB’s inflated direct and indirect CI values, most Midwest corn ethanol—even ethanol from many of the plants that secured new pathways via Method 2A/2B—will not be viable for compliance this year or next.”

View the letter and a series of attached charts here.